This invention relates to a method and structure by which a tubular member or part is connected, plug and socket like, in a high torque and pull resistant, fluidtight engagement with a fitting or other body member. Such assemblies of tube and fitting, and the like, have a wide range of uses, including use in relation to gas stoves.
More particularly, this invention also relates to a new and improved pilot light harness comprising an assembly of a pilot light gas supply tube (hereinafter referred to as a "pilot tube"), one end of which is sealingly inserted in a pilot tube manifold or fitting, and which has disposed on the other end a fitting or structure to ensure a steady pilot flame. Conventionally, a single manifold supplies two pilot tubes, though a single pilot tube or several pilot tubes may be supplied from a pilot tube manifold.
Gas stoves of the type that are commonly used in kitchens for cooking purposes, are provided with burners which are conveniently lighted by flashing or projecting a normally restricted pilot flame, through a flash tube. One end of the flash tube is disposed next to the pilot flame, and the other end is disposed near the burner so as to place the burner in flame communication with the pilot flame, enabling gas issuing from the burner to be ignited. Typically, the pilot flame burns continuously, and will ignite any flammable gas reaching it. Thus, it is of utmost importance that there be no gas leaks from any portion of the gas supply system to the stove. In particular, because normally there is a continuous flow of gas through a pilot tube manifold and the one or more pilot tubes emanating from the manifold, it is necessary to effect a reliable and rugged gastight seal between each pilot tube and the manifold. Ruggedness of the seal is desirable for two reasons: the pilot harness may be handled roughly when it is fitted into a stove, or at some point during the manufacture of the stove, and the pilot harness is likely to be roughly contacted on occasions when the stove is in use as it is being thoroughly cleaned.
Prior art devices to seal the pilot tube in flow communication with a source of gas include a valve and coupling such as disclosed in U.S. Pat. No. 3,527,410. Such a valve may include a single fitting extending axially from the end of a pilot tube and obviating the need for a separate coupling and valve mechanism, without leakage or similar danger. However, where economics preclude the use of a valve such as is disclosed in the aforementioned patent, it is desirable to sealingly insert a pilot tube into a manifold directly, without benefit of a valve. Such a seal has been effected by slidingly inserting a pilot tube into a recess in a pilot tube manifold and exerting sufficient pressure on the manifold immediately surrounding the pilot tube so as to work the metal in the manifold against the cylindrical surface of the pilot tube, compressing the tube inwardly thus effecting a seal. A seal has also been effected by press-fitting a pilot tube into a recess having a diameter no larger than the tube, and usually, sufficiently smaller than the tube to work, or pare, or shave back enough metal around the tube to effect a seal.
Seals effected as described immediately hereinabove have resulted in a frangible seal, that is, a seal which will not withstand rough handling even if it is not easily disrupted. The risks of utilizing seals such as these have been deemed undue by certain governmental agencies. There is, therefore, a need for supplying an inexpensive pilot light harness in which the tubes are sealingly inserted in a pilot light manifold to form a rugged seal.
It is also obvious that such a structure whereby a tube and fitting can be formed into a fluidtight juncture which resists disjuncture due to axial or torque forces or because of return of the metal of the juncture to normalcy due to environmental or other causes following the imposition of surface and related stresses during formation of the juncture has the potential of a wide range of uses and applications beyond that in a pilot light harness.